Research Of Soil Water Distribution And Dynamic Characteristics Under The Coal Mining Condition

Shenfu-Dongsheng mining area is located in an arid and semi-arid region of northwestern China, with dry climate and extremely scarce water resources. With the durative development of coal mine resources, it made the ground collapsing extensively and ground water level decreasing to a large extent , so that the water resources is scarce seriously and the geological and entironmental problem is prominent increasingly. Thus, it is considerably significant to study the vadose zone moisture distribution and dynamic characteristic under the condition of coal mining subsidence in this area. It is not only has a practical meaning to restore the environment of coal mining and implement land reclaimation of collapsing area, but also has a theoretical meaning to extend the studies of vadose zone moisture with mining collapsing conditionThis paper takes Shenfu-Dongsheng mining area as the study area, and chooses two primary regions called Daliuta testing ground and Bulianta testing ground as stable subsidence and initial subsidence respectively. Focusing on the problems following: (1) the characteristic of soil physical and chemical properties in coal mining subsidence area; (2) soil water distribution of various collapsing type under the coal mining condition; (3) seasonal dynamics of soil water under the coal mining condition; (4) soil water spatial variability under the coal mining condition; (5) the influence on entironment by the subsidence of coal mining. The results indicated that:1,A comparison of soil physical and chemical properties between coal mining subsidence and native area showed that the mine soil granularity is more coarse than that of native soil , and the bulk density of mine soil is larger than that of native soil .2,Through the analysises of soil water content and water-storing capacity , we found that the soil water-holding capacity is decreasing prominently under effect of coal mining subsidence .3,The dynamic characteristic of soil water content with seasons are similar at all depths between subsidence area and the native area. It shows that coal mining subsidence had little impact to the seasonal dynamic characteristic of soil water content in the testing ground.4,Coal mining subsidence had a large influence on the vertical variability of soil water content. That is the coefficient of variation tended to be higher at all depths in the subsidence area than the native area. The study results of horizontal variability of soil water content in the testing ground showed that the low value of soil water content lies in the collapse crater of subsidence area. It proved that the collapse crater and collapse cave in the surface ground affect the soil water content remarkably.5,Coal mining subsidence have serious impact on all of the soil condition , water condition, environmental contamination and plants living of ground . So that it makes the entironment of coal mining area deteriorated and affects the local sustainable development critically.